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Low-dimensional model of turbulent mixed convection in a complex domain

Bailon-Cuba, Jorge and Shishkina, Olga and Wagner, Claus and Schumacher, Joerg (2012) Low-dimensional model of turbulent mixed convection in a complex domain. Physics of Fluids, Vol. 2 (10), pp. 1-20. American Institute of Physics (AIP). DOI: 10.1063/1.4757228. ISSN 1070-6631.

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Official URL: http://dx.doi.org/10.1063/1.4757228

Abstract

We construct a low-dimensional model (LDM) of turbulent mixed convection in a Cartesian cell with in- and outlets and local sources of heat which is narrow in one of the two horizontal space directions. The basis is a high-resolution three-dimensional direct numerical simulation (DNS) record. The model is derived with basis functions, which have been obtained by a proper orthogonal decomposition (POD) using the snapshot method. The POD analysis is applied for a sequence of three-dimensional snapshots aswell as for datawhich are bulk-averaged in the direction of narrowextension. This step is taken since the flow is found to have no significant dependence along this direction in the cell. We compare the three-dimensional and two-dimensional POD modes. This simplification reduces the complexity of the problem significantly and allows us to construct and run a two-dimensional LDM with a small number of degrees of freedom. We study the long-time dynamical behavior of this system using a closure of the LDM based on a mode-dependent viscosity and diffusivity. The LDM has been optimized in terms of the standard deviation of the energy spectrum and the transient energy for different numbers of degrees of freedom by comparison with the original DNS data. We find that the evolution of the coherent structures of flow and temperature agrees well with the two-dimensional original data and determine their contribution to the global transfer of heat. Root-mean-square profiles of the fluctuations of the turbulent fields agree qualitatively well with the original simulation data, but deviate slightly in amplitude. We conclude that the reduction in the dimensionality and the number of degrees of freedom can reproduce the gross features of the mixed convection flow in this particular setup well.

Document Type:Article
Additional Information:ISSN Online: 1089-7666
Title:Low-dimensional model of turbulent mixed convection in a complex domain
Authors:
AuthorsInstitution or Email of Authors
Bailon-Cuba, Jorgejorge.bailon-cuba@tu-ilmenau.de
Shishkina, OlgaOlga.Shishkina@dlr.de
Wagner, Clausclaus.wagner@dlr.de
Schumacher, JoergJoerg.Schumacher@tu-ilmenau.de
Date:2012
Journal or Publication Title:Physics of Fluids
Refereed publication:Yes
In Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:Vol. 2
DOI:10.1063/1.4757228
Page Range:pp. 1-20
Publisher:American Institute of Physics (AIP)
ISSN:1070-6631
Status:Published
Keywords:mixed convection, Direct numerical simulations, proper orthogonal decomposition, low-dimensional model
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Transport
HGF - Program Themes:Terrestrial Vehicles
DLR - Research area:Transport
DLR - Program:V BF - Bodengebundene Fahrzeuge
DLR - Research theme (Project):V - Next Generation Train (old)
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Fluid Systems
Deposited By: PD Dr. habil. Olga Shishkina
Deposited On:12 Nov 2012 15:17
Last Modified:12 Dec 2013 21:49

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